Starting ignition timing
| Starting ignition timing |
Starting ignition timing is active from the point when the engine starts until the engine speed has reached the requested idling speed.
The ignition timing is normally 10° BTDC but is retarded when the temperature of the intake air rises. When the temperature of the intake air reaches 70°C, the ignition will be 7° ATDC. The ignition retardation when the air temperature increases is caused by the similar increase in combustion velocity.
When starting, the control module triggers each cylinder with a 200 Hz signal for 60 crankshaft degrees, whereby a so-called multi-spark occurs. When the engine speed exceeds 450 rpm, the frequency will be increased to 330 Hz. The function ceases when the engine speed exceeds 650 rpm. If the engine speed drops below 450 rpm again, the function will be restarted provided the coolant temperature is below -10°C.
This is to ensure ignition in unfavourable starting conditions and to prevent the engine from stalling directly after start.
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